As long as your ex-husband
is going to drive the vehicle and park it as his residence, he can insure your car under his name and policy. Because you own it, you would need to be listed as an additional interest in the policy. This would ensure any claims checks would be paid to you rather than your ex-husband in the event of an accident.
However, if you're going to be using the vehicle and it will be at your residence the majority of the time, you cannot. To do so would be committing insurance fraud
and you risk having your coverage denied in the event of an accident. Although it is expensive, car insurance is mandatory. I would recommend comparing several different quotes
to ensure you are getting the best price. Also, remember that the quotes you are seeing reflect your current lack of insurance. This means that after six months with car insurance, you will likely see a decrease in your insurance rate. Best of luck!